The field of the invention pertains to the secure anchorage of child safety seats (CSS), which are held in place in an automobile by the conventional seat belt. In particular, the invention pertains to a convenient and effective means to securely tighten the automotive seat belt about the frame or primary structure of the child safety seat to restrain the seat in the automobile. In this particular embodiment, the automobile seat belt is not used to restrain the child in the CSS, because the CSS comes equipped with a separate harness or other restraining system for the child.
Numerous means have been invented to tighten fabric or metal straps wrapped about one or more objects. These devices come in the form of clamping means or tightening and adjusting means with a mechanical assembly that engages a portion of the strap or, alternatively, two separate portions of the strap. Most of these devices, however, require that at least one end of the strap be passed through the device after the device is attached to another portion of the strap. U.S. Pat. Nos. 1,963,436 and 4,388,748 each disclose clamps that are affixed to one end of the strap and reel up the other end of the strap to clamp and tighten the strap about some object. Both of these references disclose a bifurcated pin through which the strap is passed and which may be rotated to reel up the loose end of the strap thereby tightening the strap. A latching or ratcheting means is provided to prevent the strap from loosening from the tightened position. In both cases the clamp is completely assembled and the loose end of the strap inserted through the slot in the bifurcated pin or reel.
U.S. Pat. No. 4,324,023 also discloses a bifurcated reel in a ratchet buckle for a seat belt, and U.S. Pat. No. 3,826,473 discloses a strap tightener that may be positioned at any intermediate location along a strap. The latter includes a bifurcated reel for rolling up the strap and a ratcheting mechanism for retaining the tightened position. Both of these references also require that the seat belt or strap be attached to the reel by passing one end of the seat belt through the bifurcated slot. The tightening or clamping means is completely assembled and operational before the end of the strap must be passed through the bifurcated slot and the reel turned to tighten.
Conventional automobile seat belts are equipped with a tightening an/or retracting device on at least one of the two belt halves. These can be either manual or automatic. In modern seat belts, the automatic retracting devices are normally mounted on the floor of the car and include a ratcheting or emergency inertia locking mechanism. A buckle attaches the two halves of the belt about a person or the frame of a child safety seat. Seat belts without the automatic retracting device include a manual tightening mechanism incorporated in the buckle. Unfortunately, with all three seat belt mechanisms, it is very difficult to fully tighten the seat belt about a child safety seat frame to assure that the seat is firmly anchored to the vehicle. The automatic ratcheting mechanism is purposely difficult to fully tighten, thereby providing some measure of comfort to the adult wearer. The inertia locking mechanism provides no tightening except under emergency conditions; thus, the child safety seat may shift out of position further loosening the belt during normal driving manuevers. The manual buckle tightening mechanism may find itself located underneath the child safety seat, and thus be inaccessible or awkward to manipulate.
The devices illustrated in the prior art above all require that one end of the seat belt or strap be passed through the bifurcated slot of the pin. With the buckle parts on each end of an automotive seat belt, neither end can be passed through such a bifurcated pin. Thus, such devices are not suitable for final tightening of an automobile seat belt.